Hacker News Reader

Comment by jabart | Hacker News Reader

New homes should be built to better insulation standards. You have to solve so much and use so much energy to solve for a drafty house or lack of insulation on the outside walls. Newer homes are factoring in the R-value of 2x6s and finding ways to insulate those now.

In this scenario, high efficiency heat pump with a backup gas fireplace. Those typically don't require any electricity to run as they can ignite off AA battery or a push button. My PC battery backups barely last 30 minutes on a wifi router because of conversion loss. Furnace fans also account for up to 1/3 of energy usage of a unit. Cogneration would add $5-10k to a home build versus a 50 gallon propane tank with a single emergency gas fireplace unit.

View on HN

If you've got wood available, you could also have a wood furnace as backup, and / or an actual fireplace (an efficient one ideally, possibly a masonry heater if you have the space and foundations to handle that load).

This is a great solution too. I have a wood 'heatilator' (or fireplace insert) and during the recent cold snap in the Midwest I went through about 1/4 face cord of kiln-dried oak over 3 or 4 days (that's a lot by my standards). It kept the gas furnace mostly idling and the home warm (in the 80's by the fireplace actually, lol). Probably not exactly cost efficient with the cost of wood these days but I like being able to take some of the load off the gas furnace.

Most of the heat from a fireplace goes up the flue unfortunately. It’s one of the least efficient heating sources per the dept of energy (~15% efficient). A low tech solution is more thermal mass perhaps in high performance dwellings.

Wood burning furnaces are a challenge because homeowners insurance providers don’t want to insure dwellings that use them (but will if certain conditions are met, such as it not being the primary hearing source, professionally installed, etc).

Wood stoves are really efficient these days, hitting 70% plus, and it's Carbon Neutralish™ as a fuel source (obviously uses fossil fuels for harvest and transport and such, but that's only some percentage of the total)

I'm always amazed at the ability of our questionable 1990s wood stove to happily heat the entire house. It's a great backup heat source on days when it gets proper cold out, which is thankfully rare here.

> Most of the heat from a fireplace goes up the flue unfortunately.

Depends on the fireplace. Direct-vent gas fireplaces take outside air for combustion and then exhaust it, with no inside air being used in the process. There are also direct-vent wood stoves that can do the same.

Wood stoves can get about 85% combustion efficiency, but that's not heat-delivered efficiency (often 10-20% lower):

* https://www.epa.gov/burnwise/energy-efficiency-and-your-wood...

This is why very old homes have absolutely massive fireplaces in the center of the house - the huge size led to a massive thermal mass that would extract most of the heat from the circuitous smoke path inside.

The advantage of wood is you can burn it without any outside source of anything.

Reply on news.ycombinator.com